The present invention relates to a method of edge glueing and to a tensioning aggregate which is provided for a device for edge glueing.
During edge glueing an edge hardening medium which will be referred as a glue later on, is applied to the edges of a textile product web. The hardening of the edges is provided for preventing a rolling-in on the edges during making the product ready. The tendency of the non treated edges to roll in is very high in knit wear. In some weave wear there is a tendency of edge fringing. This is prevented by hardening of the edges.
The German patent document DE 12 26 978 discloses a process in which an expanded product web is sprayed with glue at its edges with stationary spraying nozzles under which the product web is transported. Immediately after the spraying, the glue is dried by a drying device with hot air. The spraying nozzle disclosed in this reference is problematic with regard to exact dosing of the glue.
An improved dosing is performed in an edge glueing device disclosed in the German document DE 38 34570A1, which is arranged at an input of a tensioning frame and has an application roller which partially dips into a trough filled with glue. The periphery of the application roller comes in contact with edge strips of the material web held for example in a needle chain. The application roller which is set in rotation by the material transportation, transports the glue as throughgoing strips or in form of transverse lines, in the event if the periphery of the application roller has an inclined toothing, onto the material web. The corresponding tensioning aggregate provided with an edge glueing device with application rollers is known from the catalog “Synergie-Spannrahmen KTT 2000” of Babcock Textile Maschinen GmbH.
During the application of the glue by an application roller the application quantity depends on the dropping speed, or in other words on the viscosity of the glue, on the surface quality of the glue wheel and the tendency of the glue to form a dried liquid surface, and on the advancement, the absorption of the product and the speed of the web. The application quantity therefore can not be arbitrarily selected in view of the above listed factors.
In the German document DE A2 29 054 a material web is provided with an edge hardening of linear elements, whose expansion components perpendicular to the edge extend transversely to the extension components parallel to the edge. This makes possible a hardening of the edges without disturbing elasticity loss in the material web longitudinal direction.
A further problem in the edge glueing is the drying of the applied glue. The application of the glue is also performed after the last moisturizing stage of the textile process and before the drying stage. In this case the drying must be adjusted to the higher water content of the product web edges by the glue from up to 15%. For this purpose special drying devices in tensioning frame dryers are disclosed for example in the patent document Z 37 06 615 C2, DE 81 11 908 UNDE 195 25 545. When the glue application is performed after the drying of the product web, an initial drying device is required.
It is known from the German patent document DE 195 22 124 A1 it is known to use, instead of conventional water containing synthetic plastic dispersions, melting adhesives as a glue. The melting adhesives are applied at a temperature of 150-200° C. and hardened in several seconds without a drying device. However, for melting of the glue, it requires special application devices provided with heating means, such as for example spray application heads, single hole valves or slot valves.
German patent document DE 195 06 294 A1 discloses a UV hardenable, water free synthetic plastic as a further hardening agent for hardening of the edges of threaded webs. The synthetic plastic is applied with a pattern such as transverse strips, circles, meanders, etc. with freely remaining cutting edge and subsequently hardened by UV light of a UV lamps.